Furnace



Jan. 30, Q KELLY FURNACE Filed Nov. 8, 1928 5 Sheets-Sheet l Jan. 30,1934. Q KELLY 1,945,224

FURNACE Filed NOV. 8, 1928 5 Sheets-Sheet 2 @WL l l 'I www rllll FS( @j@0W f//f O. KELLY Jan. 30, 1934.

FURNACE Filed Nov. 8, 1928 5 Sheets-Sheet 3 @fifa/1 Jan. 30, 1934. o,KELLY l 1,945,224

FURNACE v Filed Nov. 8, 1928 5 Sheets-Sheet 4 o. KELLY 1,945,224

FURNACE Jan. 30, 1934.

5 Sheets-Sheet 5 Filed Nov. 8. 1928 Patented Jan. 30, 1934 UNITED STATESPATENT OFFICE 2 Claims.

My invention relates more particularly to furnaces of the self-stokingtype.

It has been found in practice that furnaces as hitherto constructed,where the coal is fed directly from the bin to the grates, present thedisadvantage of crowding the fire-bed with more or less raw coalregardless of the grade or kind commonly used, resulting in theproduction of a smoky fire even under forced draft, the amount of Vsmokeproduced being much greater where the coal is supplied to the bins inmore or less wet condition, as is the common practice, andis fed to thenre-bed before it has become comparatively dry and heated to theignition point.

Furthermore, in addition to the above disadvantage which is much morepronounced where the cheaper grades of coal, such as that in the form ofslack, or nut and slack is used, and particularly where such grades ofcoal are used under low, natural, draft, furnaces as hitherto providedpresent the objection, when the cheaper, ner, grades of coal are usedparticularly under low, natural, draft, of presenting undue resistanceto the passage through the fire bed of suflicient air for producingproper combustion due to the presence in the fire-bed of an excess offine particles of coal causing the bed to be so compact asto present theresistance referred to.

Furthermore, relatively great waste of fuel results due to the droppingof the finer particles through the openings in the grates.

One of my objects is to prevent production of a smoky fire even whenrelatively wet coal containing fine particles is fed from the bin to thefurnace and the furnace is operated under low, natural, draft.

Another object is to accomplish the above stated purpose and to utilizein the furnace the heat values in the finer particles of coal.

Another object is to provide improvements in furnaces to the end thatgreater economy in the operation thereof may be effected by thesubstantially complete combustion of the fuel.

Another object is to provide for the burning of relatively fine coalparticularly slack, under low natural draft without danger of thechoking of the fire bed with resultant decrease in efficiency andincomplete combustion, and other objects as will be manifest from thefollowing description.

Referring to the accompanying drawings:

Figure 1 is a view in side elevation of a hot Water or steam boilerembodying my improvements.

Figure 2 is a view in longitudinal sectional elevation of the furnace,the section being taken through the center line of the furnace withcertain parts thereof shown in elevation.

Figure 3 is a broken end view of the furnace viewing it at the line 3 onFig. 2 and in the di rection of the arrow. g

Figure 4 is a perspective view of that portion of the furnace to whichthe fuel is initially fed and a portion of the mechanism for feeding thecoal thereto. J

Figure 5 is an enlarged detailedview taken at the line 5 on Fig. 4 andviewed in the direction of the arrow.

Figure 6 is a perspective view of one of a number of similar trunnionbearings forming a part of one of the coal feeding means, this figureincluding a phantom showing of the plate carrying these bearings at oneside of the structure.

Figure 7 is a perspective view, partly sectional and with certain partsomitted, of the grate structure of the furnace..

Figure 8 is a View like Fig. 2 of a hot air furnace embodying myinvention.

Figure 9 is a view of somewhat diagrammatic character of the operatingmechanism of the furnace of Fig. 8 for actuating the coal feeding meansthereof. y

Figure 10 is a section taken at the line 10-10 on Fig. 2 and viewed inthe direction of the arrows; and l A r Figure 11, a section taken at theirregular line 11-11 on Fig. 2 and viewed in the direction of thearrows. .A

Referring to Figs. 1 to 7, inclusive, and 10 and 11 the furnace thereinshown is formed of a horizontal series of separate, vertically disposed,hollow sections 10 forming water chambers each formed at its lower endwith spaced apart waterleg portions, these portions'at one side of thefurnace being represented at 11.

All of the sections 10, except the forwardmost one thereof, contain attheir upper portions a horizontal series of horizontal gas nues arrangedside by side and preferably three in number, these flues beingrepresented at 12, 12a,and 12b. The middle flue 12 opens at its rearendinto a stack 13 and all three of these ues open -at their forward endsinto a cross flue 14 formed in the forwardmost one of the sections 10and extending entirely across the three ,flues referred to. All of thesections 10, except the forwardmost one thereof, contain openings 15therethrough which together form a chamber 16 located below and out ofdirect communication with the ilues above referred to, this chamberbeing located midway between the sides of the furnace and beingrelatively narrow compared with the width of the sections 10 the chamber16 communicating at its forward end with the space 17 defined by thewater-legs of the forwardmost section 10.

The bottom of the chamber 16 is formed of a horizontal series of hollowcross members 18 forming water-chamber portions of certain of thesections 10, thesecross members, except the one thereof on therearwardmost section 10, being spaced apart as shown to provide spacestherebetween for a purpose vhereinafter described. The cross member 18of the one of the sections 10 next to the rearwardmost one thereof ispreferably relatively deep at its forward portion as shown at 19 and therear portion of the cross member of the rearwardmost one of the sections10 is also relatively deep as represented at 2O thereby providing ahorizontal gas-passage 21 which opens, at its opposite ends, intoupwardlyextending flues 21a and 21b in these two sections 10communicating with the rear ends of the flues ,forming and stokingmechanism shown comprises ya series of stationary grate sections 23extending entirely across the combustion chamber 22 these grate sectionsbeing spaced apart vertically and arrangedin the form of steps as shown.

Interposed between adjacent ones of the stationary grate sections 23 aregrate sections 24 mounted to be reciprocated lengthwise of the furnaceand operating to advance the fire bed toward the rear end of the furnaceand replenishing the fire bed with fuel delivered thereto at the frontend of the furnace as hereinafter described.

The movable grate sections 24, together with a plunger member 25 locateddirectly above the uppermost stationary grate section 23, are rigidlyconnectedtogether at opposite sides of the furnace by brackets 26 oneonly of which is shown, the plunger 25 being directly connected withthis bracket and the reciprocable grate sections 24 g connected theretoas through the medium of the `rods 27.

The brackets 26 are each formed with a rack portion 28 which meshes witha rack-segment 29, vthere being two o-f these segments, one at each sideof the furnace and rigidly connected with a rock shaft 30 actuated ashereinafter described.

Located in the chamber 16 is a trough-likemember 31 the bottom of whichis apertured at 32, preferably slotted as in the case of ordinary Igrateconstructions, the rear end of the bottom of the member 31 curvingupwardly and rearwardly as represented at 33 and terminating in ahorizontal rearwardly-extending plate-extension 'i34- outside of themain furnace structure, the 'trough member 31 forming, in effect, acombined 'coking plate and conveyor trough in which the 'coal to beconsumed in the furnace is subjectedto 'a bin the lower spout portion ofwhich is represented at 35, the outlet of this spout extending directlyabove, and opening into a trough 36 the bottom of which is formed of theplate 34, this trough being located in direct line Awith the trough 31.

Means are provided for feeding the coal into the rear end of the trough31 and thence therethrough for discharge at its forward end upon thegrate. These means comprise a plunger 37 reciprocable across the outletof the spout to feed the coal into the rear end of the trough 31, anddrag mechanism operating in the trough 31 to move the coal along thebottom of the trough to the front end thereof.

The drag mechanism shown comprises a pair of bars 38 mounted on theupper edges of the sides 39 of the trough 31 to be reciprocable thereon,the plunger 37 being mounted on the rear ends of these bars,intermediate portions of which latter, and represented at 40, form thesides of the trough 36. The drag mechanism also comprises a series ofdrag-plates 4l located between, and extending crosswise of, the bars 38'and swingably mounted thereon at trunnions 42 located at the upperedges of these plates at opposite ends thereof, the plates beingpreferably of wedge shape in cross-section as shown.

Each bar 38 is provided, adjacent the endsof the trunnions 42 with guidelugs 43. These lugs are preferably of the form shown presenting acentral portion 44 containing a semi-circular recess 45 in its upperedge to receive a trunnion 42, andend portions 46 and 47 located atopposite sides of the portion 44 and depending below the underside ofthe part 44, the portion 47 affording a stop surface 48.

The bottom edge portions of the bars 38 ar recessed to receive theportions 44 of the lugs 43 as shown in Fig. 6, the bottom edges of theportions 44 and bars 38 being iiush and the portions 46 and 47 of thelugs depending below the lower edges of the bars 38 and forming guidesfor preventing displacement of these bars on the side walls 39 of thetrough 31 in the reciprocatory movements of said bars. The lower edgesof the bars 38 contain semi-circular recesses 38a in registration withthe recesses 45 in the lugs 43, the recessed portions of these bars andlugs forming -journals for the ends of the trunnions42.

The drag mechanism also comprises bars 49 extending lengthwise of thetrough 31 at opposite sides of the latter and connected together attheir rear ends by a tie-rod 50, and at their forward ends, at upwardlyprojecting extensions thereof, by a rod 51 which is slidable on theupper edges of the bars 38, the latter presenting stop 38a for a purposehereinafter described.

The bars 49 contain at intervals Vertical slots 52 into which the ends53 of cranks 54 provided on the outer ends of the trunnions 42, extend.The rear ends of the bars 49 are formed with rack portions 55 which meshwith gear-segments 56 (one only of which is shown) secured `to the endsof a shaft 57 journalled on the furnace structure.

In the construction shown the reciprocatory -grate sections 24 andplunger 25 and the mechanism for actuating the plunger 37 and moving thecoal through the chute 31, are operated from a single power device,which may be of any desirable construction. That shown is Vin the formof a fluid-pressure-operated piston and cylinder mechanism representedat 58 the cylinder of which is shown at 59, and may be of any suitableconstruction, it having a valve mechanism (not shown) operated by a rockshaft 60 having a Crank 61 which, in its partialrotation in ODPOAStedirections, controls the inlet of fluid pressure to the opposite ends ofthe cylinder 59 and the exhaust therefrom for effecting reciprocation ofthe piston therein.

The piston of the mechanism 58 is connected, by a stem 62, to a bar 63provided with an arm 64 connected with the crank 6l, and having rackportions 65 and 66, the rack portion 65 meshing with a gear segment 67journalled on a shaft 68.

This gear segment is equipped with two oppositely disposed pawls 69pivoted thereto as represented at 70 and cooperating with a ratchetwheel 71 journalled on the shaft 68. By this arrangement reciprocatorymovement of the bar 63 is translated into intermittent rotary movementof the ratchet 71 to which a link 72 is pivoted eccentric of the axis ofthis ratchet as represented at 73, the other end of this link beingpivotally connected with a crank arm 74 rigid on the shaft 57 therebytranslating intermittent rotary movement of the ratchet 71 intointermittent oscillatory movement of the segments 56 for reciprocatingthe plunger 37 and the drag mechanism operating in the trough 31.

The rack 66 meshes with a gear segment 75 journalled on a shaft 76 andcarrying oppositely extending pawls 77 pivoted thereto at 78 andcooperating with a ratchet wheel 79 journalled on the shaft 76, thisratchet wheel being connected, eccentrlcally of its axis, with one endof a link 80, as represented at 81, the opposite end of this link beingpivotally connected with a crank 82 rigidly connected with the shaft 30whereby reciprocato-ry movement of the bar 63 is translated intointermittent reciprocatory movement of the grate sections 24 and plunger25, it being preferred that, as shown, the paWls 69 and 77 are sodisposed that the plunger 37 and drag mechanism are operated only whenthe bar 63 moves in one direction and the movable grate sections andplunger 25 are operated only when this bar moves in the oppositedirection, this being desirable as thereby the minimum power is requiredfor cperating these mechanisms. v

A description of the operation of the furnace is as follows:

Referring now to the operation of the plunger 37 and the drag mechanism,assuming that the bars 49 are in the extreme back position to which theyare moved by the gear segments 56 as shown in Fig. 2, in which positionthe plunger 37 is withdrawn from a position in which it closes theoutlet of the chute 35 and the drag plates 41 assume substantiallyhorizontal position as shown, the initial forward movement of the bars49 rotates these plates downwardly and forwardly to a position in whichthey engage the stop surfaces 48 (Fig. 4) of the lug 43, whereuponcontinued forward movement of the bars 49 moves the bars 38 bodilyforwardly and the plates 41 and plunger 37 connected therewith, theplunger operating to feed a charge of coal into the trough 31 and thedrag plates advancing along the trough the coal in the front of them.Upon the beginning of the rearward stroke of the bars 49 the drag plates42 first swing into the position shown in Fig. 2 at which time the tierod 51 engages the shoulders 38b on the bars 38. The continuing rearwardmovement of the bars 49 thus moves the bars 38 and the parts connectedtherewith to their rearwardmost position as shown in Fig. 2.

It is preferred that the drag plates 41 be spaced apart a distanceslightly less than their horizontal travel, so that these plates inswinging to vertical position will always become positioned be- It isalso preferred that the radius of the curved portion 33 of the trough 31be substantially equal to the height of the rearwardmost drag-plate 41,

as shown, whereby this drag-plate, in engaging' the coal pushed into thetrough 31 by the plunger 37, sweeps downwardly and forwardly with itslower edge close to the curved portion 33 and as the plunger 37 may becaused to deliver an equal amount of coal at each stroke, choking orsticking of the drag mechanism thus may be avoided.

Referring now to the operation of the combined grate and stokingmechanism, recip-rocation of the movable grate sections 24 and theplunger 25 operate to advance the co-al along the grate, feeding thecoal to the upper front end thereof and discharging the ashes at therear end portion of the grate. It being preferred that the space betweenthe rearwardmost grate section 23 and the rear wall of the furnace beprovided with a plate 83 secured at its rear edge portion to a rockshaft 84 equipped with a counterweight 85 causing the plate 83 tonormally close the space referred to, this plate normally incliningupwardly and rearwardly and extending into the path of the'forwardmovement of the lowermcst movable grate section 24 the plate 83 beingmoved to open position to discharge any clinkers thereon, by engagementtherewith of the grate section referred to.

In the movement of the coal along the trough 31 the coal is thussubjected to the heat generated by the re bed on the grate causing it tobecome heated with the result of drying the coal and at least partiallycoking it, the finer particles of the coal dropping through theapertures 32 in the trough and upon the hot fire bed below, and, beingin dried and heated condition, these finer particles readily ignite,very much the same as in the case of gas, with almost completecombustion.

The coal in passing through the coking trough 31 will give off more orless of the volatile matter therein and this gas mixed with air enteringthe chamber 16 thro-ugh .openings 86 in the rear Wall of the chambershown as located immediately above the racks 55 and controlled byswinging doors 87 and which becomes heated in the cham'- ber, travels,under the action of the draft in the stack 13 along the chamber 16 tothe front end thereof and thence into the combustion chamber above thefire bed where it will be burned without waste or smoke.

The coal which is thus delivered to the grate sections, is in dried andpreferably at least partially coked condition, thereby eliminating theproduction of smoke and ensuring practically complete combustion of thecoal supplied to the furnace.

Referring now to the construction shown in Figs. 8 and 9, thisconstruction constitutes a desirable embodiment of my invention forincorporation in a hot air furnace.

In this construction the outer shell of the furnace is represented at88, this shell having a cold air inlet in the form o-f a screen 89 atits lower end and an outlet 90 at its upper end for the heated air.

Located within the shell and spaced therefrom and out of communicationtherewith is a combustion chamber 91 having a combined grate and stokermechanism at the lower end thereof as represented at 92 and of the sameVgeneral construction as that shown in Fig. 2, the shaft by which thismechanism is operated, and corresponding with the shaft 30, beingrepresented at 93.

Above the combustion chamber 91 is a chamber 94 and corresponding withthe trough 31, the bottom of this chamber being apertured as representedat 95 and as shown and described of the bottom of the trough 31, theforwardend of the chamber 94 being open for discharge therethrough andupon the grate and stoker mechanism below it, of coal advanced throughthis chamber as hereinafter described.

The rear end of the chamber 94 communicates with the spout portion 96 ofa coal bin not shown and through which the coal flows into the chamber94.

The combustion chamber 91 is provided with vertical flues located atopposite sides of the chamber 94 which open into horizontal flues (notshown) in which the products of combustion pass forwardly to the frontend of the furnace and thence upwardly to a series of horizontalflues 97in communication at their rear ends with the stack 98.

The chamber 94 is shown as provided with a spiral conveyor 99 comprisinga shaft 100 journalled at its forward end in the front wall of thefurnace and at its rear end in a bearing 101 at the rear end of thechamber 94, this conveyor operating to feed the coal supplied from thespout 96 along the chamber 94 forthe purposes described in connectionwith the construction of the preceding figures. Air is supplied to thechamber 94 through damper-equipped openings 102 in the rear wall of thefurnace (one only of such openings being shown) this air mixing with thegases evolved from the coal as it passes along the chamber 94, the onlyoutlet of this chamber being into the combustion chamber 91 whichcompels the gases referred to to travel through the combustion chamberon their way to the stack 98.

The mechanism for operating the conveyor and the combined grate andStoker mechanism and which preferably is so constructed as tov operatethese two mechanisms alternately as in the case of the construction ofthe preceding figures of the drawings, comprises a reciprocable bar 103actuated by mechanism represented at 104 and shown as of the sameconstruction as that illushaving pawls 109 for intermittently driving a:

ratchet wheel 110 having a crank 111 pivotally connected with one end ofa link 112 the other end of which is pivotally connected at 113 withacrank 114 on the shaft 93.

The other rack portion 106 meshes with a gear segment 115 pivotallysupported on a shaft 116 and having pawls 117 operating tointermittently drive a ratchet wheel 118 fixed on the shaft 116, theshaft 116 being connected through bevel gears 119 and 120 with the shaft100 thereby operating p to intermittently rotate the conveyor 99.

While I have illustrated and described certain embodiments of myinvention, I do not wish to be understood as intending to limititthereto as the same may be variously modified and altered and theinvention embodied in'other forms of construction without departing fromthe spirit of my invention.

What I claim as new, and desire to secure by Letters Patent, is:

l. In a furnace, the combination of a grate, a coal-supporting memberarranged above said grate and subjectedto the heat generated by the iirebed on said grate, said member having an apertured bottomv fordischarge, upon said fire bed, of fine particles of coal sifting throughsaid member, means forfeeding the coal along said apertured bottom, andmeans for conducting the gases generated by the heating of the coal onsaid member into the space between said grate and member.

2. In a furnace, the combination of a combustion chamber, a grate at thebottom of said combustion chamber, a second chamber above saidcombustion chamber, and located at substantially the medianline of thefurnace, said second chamber communicating at one end with saidcombustion chamber, means for feeding coal in said second chamber fordischarge into said combustion chamber, and aseries of flues-above saidchambers the central one of which communicates at one end with thestack-outlet of the furnace and at its opposite end with adjacent endsof the others of said flues, which latter communicate at their otherends with said combustion chamber.

ORIN KELLY.

